Hypoglycemia results in a reduction in cardiac baroreflex sensitivity and a shift in the baroreflex working range to higher heart rates. This effect is mediated, in part, by the carotid chemoreceptors. Therefore, we hypothesized hypoglycemia-mediated changes in baroreflex control of heart rate would be blunted in carotid body-resected patients when compared with healthy controls. Five patients ...

Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension ...

The vascular effects of graded stimulation of the carotid chemoreceptors were studied in 13 anesthetized and artificially ventilated dogs, and stimulusresponse curves were defined. The carotid bifurcations were isolated and perfused at constant pressure, and the vagi were cut. Autologous blood collected in a reservoir was equilibrated at Po2 varying from 104 to 34 mm Hg, Pco3 from 39 to 81 mm H...

In a study of autonomic reflexes it was found that some produce a generalized, bilaterally uniform response whereas others have an asymmetric or laterality of action. Recordings from vertebral nerve fibers (mainly vasoconstrictors to forelimb muscles), right and left cardiac sympathetics, and renal nerves show that baroreceptors evoke a bilaterally uniform inhibition but chemoreceptors of the c...

Carotid baroreflex activation therapy produces a sustained fall in blood pressure in patients with resistant hypertension. Because the activation electrodes are implanted at the level of the carotid sinus, it is conceivable that the nearby located carotid body chemoreceptors are stimulated as well. Physiological stimulation of the carotid chemoreceptors not only stimulates respiration but also ...

A mathematical model of the acute cardiovascular response to isocapnic hypoxia is presented. It includes a pulsating heart, the systemic and pulmonary circulation, a separate description of the vascular bed in organs with the higher metabolic need, and the local effect of O(2) on these organs. Moreover, the model also includes the action of several reflex regulatory mechanisms: the peripheral c...

We used extracorporeal perfusion of the reversibly isolated carotid sinus region to determine the effects of specific carotid body (CB) chemoreceptor inhibition on eupneic ventilation (Vi) in the resting, awake, intact dog. Four female spayed dogs were studied during wakefulness when CB was perfused with 1) normoxic, normocapnic blood; and 2) hyperoxic (>500 mmHg), hypocapnic ( approximately 20...

BACKGROUND The peripheral and central chemoreflexes are important autonomic mechanisms for regulating breathing and cardiovascular function. Although pathological inflammatory infiltration of the peripheral chemoreceptors and central nervous system has been reported in Chagas' disease, functional evaluation of chemoreflexes has not yet been performed. METHODS AND RESULTS The hypothesis that c...

The role of the different mechanisms involved in the cardiovascular response to hypoxia [chemoreceptors, baroreceptors, lung stretch receptors, and central nervous system (CNS) hypoxic response] is analyzed in different physiological conditions by means of a mathematical model. The results reveal the following: 1) The model is able to reproduce the cardiovascular response to hypoxia very well b...